Solid state light fixtures lead to saving energy and improving the service life of the light source over incandescent bulbs and fluorescent tubes, for instance. Many light fixtures in residential and commercial application use obsolete incandescent bulbs and need to be replaced by energy efficient light fixtures.
Early 20th century incandescent light fixtures found in a bathroom, for example, featured a back plate mounted to the wall, and a lamp extending from the back plate. The lamp had an Edison light socket to receive a 60 watt or 75 watt bulb. The bulb was typically emplaced within a decorative glass or plastic lamp shade. The lamp shade had a groove at its base which was held in place by radial screws that were advanced into the groove to hold the shade to the lamp. More current lamps have the same incandescent bulb attached to an Edison socket, wherein the shade is threaded on to the socket exterior with use of a collar.